Tandem engine arrangement



. July 28, 1936.

R. S. VAN ATTA TANDEM ENGINE ARRANGEMENT Filed June 22, 1933 INVENTOR A 055 7' c). Mar/V4724 ,477' NEVJ Patented July 28, 1936 STATES PATENT OFFICE 2 Claims.

This invention relates to improved tandem arrangement of engines having more than one cylinder bank.

It is a principal object of the invention to provide in a multi-engine power plant applicable to aircraft, a cylinder bank arrangement offering minimum head resistance during flight.

It is another object of this invention to employ a tandem arrangement of engines equally applicable to fuselage or nacelle installations.

It is a still further object of the invention to select an engine arrangement which will permit the use of a propeller transmission of minimum simplicity.

With the foregoing and other objects in view, which will appear as the description proceeds, the invention consists, in certain new and novel improvements in multi-engine power plants, which will be hereinafter more fully illustrated and described in the accompanying drawing and more particularly pointed out in the appended claims.

Referring to the drawing in which numerals of like character designate similar parts throughout the several views:

Fig. 1 is a front elevation of an airplane fuselage incorporating an embodiment of my invention.

Fig. 2 is a fragmentary side elevation of the aforementioned embodiment of my invention.

In Fig. 1, a spinner I is shown fixedly attached to a propeller 2. A fuselage 3 and a radiator 4 are located immediately behind the spinner I. The right central portions of the spinner l and fuselage 3 have been broken away to show a portion of the crankcase of an engine 5 and a portion of the right-hand cylinder bank and lower extremity of an engine 6. The remaining crank- 40 case and cylinder bank portions of the engines 5 and 6 are shown in phantom. It will be noted that a crankshaft l 7 of the engine 6 is positioned adjacent to but not touching the lower right hand portion of the engine 5. The foregoing arrange- 45 ment has been made possible by maintaining maximum cylinder bank widths in substantial longitudinal alignment and so tilting the lower portions of the engines 5 and 6 outwardly that the longitudinal axes of the crankshafts I1 and 50 I9 thereof are equally spaced to right and left of the axis of rotation of the propeller 2 and that longitudinal projection of either of said axes lies well without the outer wall of the crankcase side adjacent thereto. It is self-evident that the 55 foregoing engine arrangement is equally applicable to either V (two bank) or W (three bank)- type cylinder bank arrangement.

In Fig. 2, the propeller 2 is shown fixedly attached to a driven shaft 9. The driven shaft 9 is supported at its inner end by a gear housing 5 l0 and has fixedly attached thereto a driven gear H. Driving gears 12 and I3 are fixedly attached to driving shafts I and 8. The latter gear lies immediately in back of the former gear, as shown in Fig. 2. The driving shaft 1 is operal0 tively connected with the engine 6 by means of the flexible couplings I4 and I5, shaft l6 and crankshaft I1. It will be noted that the shaft l6 passes to the immediate right of the crankcase of the engine 5, as shown in Fig. 1. The 15 driving shaft 8 is operatively connected to the engine 5 by means of a coupling l8 and a crankshaft l9.

Referring to Fig. 1, it will be noted that tandem arrangement of two aircraft engines has 20 been accomplished with retention of overall fuselage width required for but one engine. A third engine may also be added without increase in fuselage width. It will be noted that independent connection has been retained between the 25 propeller transmission and each of said tandem engines. A further advantage of the aforementioned arrangement lies in the flexible couplings separating the propeller transmission and the engines driving the same, thus eliminating strains which would otherwise be set up through relative movement between the engines themselves and relative movement between individual engines and the propeller transmission. It will also be noted that the aforementioned engine disposition permits ready access to the entire power plant with respect to servicing and maintaining the same.

I claim:

1. In an aircraft power plant, a support, a transmission secured to said support and having a driven shaft for mounting a propeller, a plurality of multi-cylinder-bank engines carried by said support, oddly disposed engines from said transmission coinciding in end profile, evenly dis- 5 posed engines from said transmission, coinciding in end profile, but the odd and even engine groups being angularly disposed with respect to one another such that the maximum cylinderbank widths of all engines are in substantial longitudinal alignment and that all crankshafts lie in a common horizontal plane, and such that the crankshaft of each successive engine may be extended parallel to and the length of the crankcase of each preceding engine, and means for operatively connecting said engines with said transmission.

one another such that the maximum cylinderbank widthsof all engines are in substantial longitudinal alignment and that all crankshafts lie in a common horizontal plane, and such that the crankshaft of each successive engine may be extended parallel to and the length of the crankshaft of each precedingengine, and gear means coupling said engines with said transmission.

ROBERTS. vAN ATTA. 10

groups being angularly disposed with respect to 

